In the manufacturing process of display devices, such as liquid crystal displays and plasma displays, conventionally, it is carried out to inspect a screen of the display device. In this screen inspection, it is performed to check the operation of manufactured display devices and confirm the presence/absence of unintended defects (point defect, line defects, etc.) on display screens.
In this screen inspection, an inspection image for inspection is displayed on each display device, while an inspection staff confirms the presence/absence of an unintended defect visually. When a display device includes an unintended defect on visual confirmation, the same display device is treated as a defective product and excluded from shipment so long as the unintended defect does not meet the quality standard for display device in terms of its position, shape, size, kind and so on (see non-patent document 1).    Non-patent Document 1: “Practical Manual for Liquid Crystal Display Manufacturing Devices” written by Ten Ikegaki and Hiroshi Wada and published by Science Forum Co. Ltd.